My laboratory has developed and applied molecular cytogenetic techniques, namely comparative genomic hybridization (CGH) and spectral karyotyping (SKY) to identify recurring chromosomal aberrations in solid tumors and hematological malignancies. CGH is a screening test for chromosomal imbalances in tumor genomes (Kallioniemi et al., 1992), and was used to analyze sequential changes in solid tumor progression after tissue microdissection of histologically defined lesions during the genesis of solid tumors. SKY allows color karyotyping of human chromosomes, therefore greatly facilitating the analysis of complex chromosomal aberrations in cancer cells (Schrock et al., 1996). SKY was applied to delineate the structural organization of chromosomal aberrations and to identify novel recurring translocations in carcinomas, sarcomas, and hematological malignancies. We were particularly interested whether:* we can identify a recurring and tumor specific pattern of chromosomal gains and losses* SKY analysis of hematological malignancies can contribute to a genetic classification of leukemias* balanced, reciprocal chromosomal translocations are significant for the genesis of solid tumors of epithelial origin * we can correlate patterns of chromosomal aberrations with tumor stage, tumor phenotype, additional pertinent genetic parameters, and the clinical course* this pattern of recurring and stage specific chromosomal aberrations bears significance in terms of diagnosis, differential diagnosis and prognostication of solid tumors when translated to cytological specimens using interphase cytogenetics - cancer, chromosome, - Neither Human Subjects nor Human Tissues